Catalysts



Patented Feb. 21, 1939 V UNITED STATES PATENT OFFICE auaais CATALYSTS.Boris Malishev, Elizabeth, N. J.

No Drawinx. Application May 3, 1938, Serial No. 205,724

4 Claims.

tion of a catalyst by calcining a mixture of sulfuricacid, sulfuric acidanhydride, sludge acid, or, generally speaking, of a substance havingacid reaction in its aqueous solution due to sulfuric acid, at atemperature from 245{ C. to red heat with a phosphate compound, such asphosphate rock, apatite, monazite, vivianite, wavelite, bone-ash, Thomasslag (finely powderedbasic slag obtained by Thomas method of makingsteel) ,-etc., these substances being mixed with diatomaceous earth orsimilar siliceous adsorbing materials. The quantity of sulfuric acid orits equivalents must be, of course, suiiicient for the completedecomposition of the mineral (or similar) phosphate, as described in myforegoing applicationsr The sulfuric acid is .largely removed by thecalcination at high temperatures used in my process.

Ihave found, however, that with my process of preparation of a catalystfrom mineral phosphates,.it is not necessary to add kieselguhr orsimilar adsorbent siliceous materials, because the.

phosphate minerals contain admixtures, especially silicium and calciumcompounds, also iron and aluminum silicates which after calcination formcalcium and other complex metal silicates and calcium sulfate. Thesecompoundsproduce with water or steam. a hard porous mass (cement andgypsum) and are, therefore, necessary for briqueting or slabbing theproduct, taking place of an adsorbing material such .as kieselguhr. Withmy catalyst, therefore, the admixture of adsorbing materials is notnecessary unless the mineral phosphate lacks suflicient amount of cementforming compounds, in which case gypsum or cement may be addedto thecalcined mass.

I have also found that these admixtures materially "enhance thecatalytic activity ofthe product, which represents a combination ofphosphoric anhydride with metal silicates or neutral sulfates, or metaphosphoric acid with the same silicates and sulfates, as follows:

Calcium I sulfate in the product will act as a catalyst itself and willalso serve as an adsorbent p material 'in place of diatomaceousearth.Calcium silicate and silicates of the cement type are present in themineral phosphate as impurities:

The catalytic activity in this case is due to the combination of metaphosphoric acid with calcium silicate (an impurity of phosphateminerals) and calcium sulfate, the latter. admixtures also replacingdiatomaceous-e'arth.

In the final product a' part of P205, probably,

is converted, into anon-volatile isomeric modification (P205) and formsa double anhydride with $102 which is-non-volatila' The briqueting or,slabbing'of the-product is also facilitated by the formation ofphosphoric anhydride when the mass is calcined with'sulfuric anhydride,this substance having binding properties, suflicient to permitbriqueting the mass. This phosphoric anhydride forms the most activecatalystbut its lifetime due to polymerization of P205 is rather shortso that the catalyst should be treated with steam if an acid catalystwith a longer lifetime is preferred.

By adding water to the calcined mixture, cement is formed with thecement-forming materials, so that the mass can be shaped into briquetsor slabs during the process of catalysis. The water of the cement andgypsum becomes liberated and converts the metaphosphoric acid, H1 03,into the more active phosphoric acid HaPOi. Such decomposition of cementis desirable to supply water in status nacendi for hy-, dration oftheacids and steam, or water must therefore be continuously added to thereaction mixture during catalysis. v v

I claim as my invention:

1. A catalyst comprising the product of a mixture of a substance takenfrom the group consisting of a mineral phosphate and Thomas slag,

witha substance taken from the group consist- I 2. A catalyst comprisingthe product of a mix-- ture of a substance taken from the groupconsisting of a mineral phosphate and Thomas slag, with'a substancetaken from the group consisting of sulfuric acid, sulfuric acidanhydride, and sludge acid, the mixture'being calcined at a temperaturesufficient to cause the first substance to be decomposed by the-secondsubstance and the free sulfuric acid to be largely expelled, but belowred heat. I

3. A-catalyst comprising the product of a mixture of a substance takenfrom the group consisting of a mineral phosphate and Thomas slag, with asubstance taken from the group consisting of sulfuric acid, sulfuricacid almanac, and sludge acid, the mixture being calcined at atemperature suificient to cause the first substance to be decomposed bythe second substance and the iree suliuric acid to be expelled, butbelow red heat, the product being hydrated for cementin'g togetherparticles of the catalyst by the cement formed .by caloination from theingredients naturally present in the first substance.

4. A step in the process of preparation of a catalyst, consisting inmixing together a substance taken from the group consisting 01' amineral phosphate and Thomas slag, with a sub- 1 stance taken from thegroup consisting of suiiuric acid, sulfuric acid anhydride, and sludgeacid. and calcining the mixture at a temperature sufiicient to decomposethe first substance by the second substance and to expell the treesulfuric acid, the quantity of the second substance being sufilclent fordecomposition of the BORIS MALISHEV.

I first substance.

